Fuel injector



May 5, 1964 c. 1 cuMMlNs ETAL FUEL INgECToR Filed Dec '7, 1961 A 0L 555/5 L. cJL/MA/f//v` CL Ess/E L. CUM/WM5 Je.

BTTOENZ Z NVENTOES l su? .y si.

United States Patent O 3,131,866 FUEL INJECTOR Clessie L. Cummins, Si) Cloudview Road, Sausalito, Calif.,

and Clessie Lyie Cummins, Jr., Mill Valley, Calif.; said Cummins, Jr., assigner to Clessie L. Cummins,

Sausalito, Calif.

Filed Dec. 7, 1961, Ser. No. 157,730 4 Claims. (Cl. 239-90) This invention relates to improvements in fuel injectors used in compression-ignition internal combustion engines.

Two problems which have faced builders of diesel or compression-ignition engines for many years are those of a steamy-white smoke exhausted upon starting the engine and of excessive sooty smoke exhausted when the engine is operating under a load. While there are other contributory causes of these undesirable exhaust smokes, a major related cause is that of insuiiicient preparation of the fuel charge before it is burned in the combustion chamber. This lack of fuel preparation results in quenched combustion in a cold engine immediately after starting and in delayed ignition when the engine is working under load.

It is, therefore, one object of the invention to provide an injector structure which better prepares the fuel charge in the plunger chamber of a mechanically actuated injector and thus materially reduce the starting smoke and the exhaust smoke under load which normally occurs in a diesel engine.

Another problem arises from the fact that diesel engines which utilize a mechanically actuated injector plunger located adjacent to the combustion chamber must provide additional means to lubricate the plunger if such an engine is used in vehicular service. During a vehicles coasting and braking cycle, the fuel ow to the injector should be stopped. However, in commercial use to date, no engine equipped with this type of injector can operate for a practical length of time without the injector plunger sticking in its bore if the fuel ow from the pump is completely shut olf.

Another object of the present invention is to enable all fuel to be shut olf to mechanically operated injectors without resultant sticking or scoring of injector plungers whenever the load is rotating the engine. This is accomplished by the use of lubrication reservoirs which provide the necessary lubrication for sutliciently long periods of time, such as during a long coast down a mountain grade.

Other objects and advantages of the invention will become apparent from the following description and the accompanying drawings in which:

FIG. 1 is a view in cross section of an injector embodying the principles of the invention, showing multi-delivery ports, lubrication bands and a double check valve construction;

FIG. 2 is a view in section taken on the line Il--ll of FIG. 1 showing the arrangement of the multi-delivery fuel ports leading into the plunger chamber;

FIG. 3 is a fragmentary view in section of a modified form of the invention in which the part of the injector which protrudes into the combustion chamber has a structure that provides more rapid heating of the fuel charge in the plunger chamber.

In FIG. 1 a fuel charge, preferably lfrom a positive displacement type of supply pump, enters an injector body through a fuel conduit 11 and hows through a cross port 12 and an axial passage to a check valve 14 located in its guide piece 15. A spring 16 serves to keep the valve 14 seated except when the fuel charge, under pressure, is passing through. The charge of metered fuel then enters an axial passage 17 in a lower check valve tube 18 and opens a lower valve 20 against ICC the pressure of a spring 21 until the valve 20 hits a stop piece 22. The charge continues down a drilled passage 23 into the body 1f) and into an annular groove 24 formed by reliefs in an injector cup 25 and the body 10. The charge finally is distributed through delivery ports 26, 27, 28 located circumferentially in the housing 10 and leading into a plunger chamber 30 formed by the retraction of a plunger 31 away from its seat in the cup 25. The plunger 31 is actuated by an engine driven cam 32 through a rocker lever 33 (shown schematically). A plunger spring 34, acting against its retainer 35, provides the force to retract the plunger 31. With the fuel charge deposited in the chamber Sti, the plunger 31 is driven downward near the end of the compression stroke by the can1`32 and in doing so drives the fuel in the chamber 30 through small spray nozzles 36 and into a combustion chamber 37.

The significance of the multi-feed ports 26, 27, 2S will now become apparent. The fuel is forced through these ports under enough pressure so that a plurality of sprays are formed which impinge on a retracted conical surface 38 of the plunger 31. The tip 38, since it is in the path of the hot air entering from the combustion chamber V3'7 through the spray nozzles 36 during the end of the compression stroke, heats up much faster upon starting the engine than its mating surface 40 on the cup 25. The injector cup 25 transfers to a cylinder head 41 and then into the cooling water much of its heat until the entire engine structure surrounding the combustion chamber approaches the normal operating temperatures. Thus the fuel upon entering the chamber 30 should strike the hotter tip 3S rather than the colder wall 46 if the fastest charge heating is to be obtained.

The purpose of the faster heating of the fuel charge in the chamber 30 is to vaporize as much of the charge as possible before it is injected into the combustion chamber 37. For, the more it is vaporized, the sooner the charge will fire when injected. This reduces the ignition delay, which in a cold engine results in the white, foggy and acrid smelling exhaust and which in a hot engine contributes to the excessive black smoke under load. It must be added that a part of the preparation of the fuel charge is due to the mixing of the fuel in the plunger chamber 35 with the hot air coming in through the nozzles 35 just prior to the bottoming of the plunger 31 in the cup 25 at the end of the compression stroke. While three delivery ports 26, 27, 28 are shown at 120 degree intervals (FIG. 2) leading into the chamber 31), the location and number of ports may vary with different engines and conditions. The reason that more than one, and usually more than two, ports are desirable is that the entire surface of the hot tip 38 should be utilized; and since the more orifices used, the smaller the percentage of fuel charge per orifice. Thus the heat transfer from the tip 38 to the fuel impinging on the tip will be more rapid. Y

FIG. 3 shows an additional method of providing faster warmup of the plunger chamber 3i). By cutting grooves 42 in the part of the cup 25 exposed to the combustion chamber 37, ns 42a are provided, and more surface area is in contact with the hot gases in the charnber 37, Aand more heat is transferred to the inner surface 40 of the cup, thus heating up much more quickly. The heating fins 42a and groves 42 perform their function most noticeably during the starting and warmup cycle, The application of additional heat to the inner'surface 40 will contribute to more efficient operation under full load also. Currently used injector cups indicate by their shiny irmer surface that the temperature inside the cup is under the ideal vaporization temperature. As the load requirements increase, the size of the fuel charge deposited in the chamber 30 also increases. The greater percentage of fuel 9 d in the chamber tends to reduce the amount of possible charge vaporization by cooling the surfaces and thus to increase the ignition delay. Y

The multi-feed ports 26, 27, 2S`also `contribute materially to the better lubrication of the lower end of the cylindrical portion of the plunger 3l. This lower zone is subject to the greatest heat and by providing lubrication with fuel to more than one point (as when the conventional single delivery port is used) the scoring or scuiiing of the plunger in this area is substantially reduced.

A study of FIG. l indicates that the injector plunger 31 has two axially extending grooves or lubrication reservoirs located toward its lower end. A lower groove 43 is separated from the chamber 3() byV a close-fitting shoulder 44 Vand from an upper groove 45 by a close-fitting shoulder 46. The upper groove 45 is also separatedV from the area above the injector body '10 by a shoulder 47. When the injector plunger 31 is driven downward to inject the previously4 deposited charge of fuel in the chamber 30 into the combustion chamber 37, extremelyV high hydraulic pressures are created in the chamber 30. A very small por-V tion of this charge will be forced upward between the close-fitting shoulder 44 and its bore in the housing 10. (Also, since the length of seal between the bottom ofthe delivery ports 26,- 27, 28 and the start of the conical surface 40 is short, another part of the charge Would be forced into the annular conduit 24 and out of the injector f if the check valve 20 were not employed. However, with good valves the only leakage is up the bore and not back through the feed ports.) Thus with each injection a little more fuel is forced upward past the shoulder 44 until the groove 43 is full of fuel. When the groove 43 is finally full, the pressure forces fuel past the shoulder 46 and into the upper groove 45. This groove 45 is open at all times to the conduit 48 which leads back to the fuel source (not shown), through an injector conduit 50. By groove 45 being Yheld at substantially atmospheric pressure, no fuel oil will leak past shoulder 47 and into the engine where it could dilute the lubricating oil. The upper shoulder y47' is lubricated by engine lubricating oil at its upper end and by fuel oil at its lower end. There are, therefore, two bands of fuel oil serving to act as plunger lubricant reservoirs when the throttle is closed and the fuel from the supply pump is shut off, as whenever the engine is coasting. These bands 43 and 44 are deep enough to provide a reservoir of suicientcapacity to take care of plunger lubrication during the longest coast.

The return line 50 leadingback to the tank is important V'for still another reason. During the time of peak gas pressures in the combustion chamber 37, as on the power stroke of the engine, some of the gas is forced into the now collapsed chamber 30, the plunger 31 being held seated at this time. The check valve 20 and its back up valve 14 prevent any gas from entering the fuel supply conduits leading from the supply pump to the chamber 30. If gas bubbles enter these conduits, a very poorly operating engine will result, as explained in U.S. Patent No.

2,997,993. However, some of the gas Will pass upward between the shoulder 44 and the bore wall of the housing 10, as did the small quantity of fuel during the time of injection. These bubbles of gas ultimately pass through the fuel in the groove 43, along the shoulder 46, in the groove45 and on back'to the vented fuel source (not c Y shown) through the passages 48. and 50. These hot gas much smaller volumes of bubbles work their way up theV plunger. In extremely long coasts the gases could carry away all of the lubrication supply in the bmds 43, 45 but,

as with all fuel pumps, it is almost impossible to prevent t some fuel from leaking from the pump when the throttle is closed. This slight seepage, therefore, enters the chamber 3G and keeps the surfaces 3S and 40 moist. The inlates, many changes in construction Yand widely differing embodiments and applications `of the invention will suggest themselves without departing from the spirit andV scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

What is claimed is: f

1. In a liquid fuel injection nozzle for the combustion chamber of an internal combustion engine, comprising a nozzle housing having a bore therein with a plunger chamber and seat at the inner end thereof and an orifice in saidseat leading into said combustion chamber, a fuel injection plunger having a cylindrical inner end portion reciprocable in said bore adjacent said plunger chamber and having its lowermost end portion adapted tol mate with said seat at the end of the injection stroke of said plunger in said plunger chamber and to provide an end wall of said plunger chamber when spaced thereabove, a

liquid fuel passage in said housing adjacent said bore Yconnected to a fuel supply, and a check valve means in said fuel passage;

the improvement comprising a liquid fuel charge dividing and distributing passage surrounding said bore adjacent the upper end of said plunger chamber, a

plurality of circumferentially spaced spray orifice means providing communication between said charge dividing and distributing passage'and said bore, each of said orifices extending radially of said bore to inject said fuel against a different circumferentially spaced heated area of said plunger end portion when said plunger is in a first predetermined portion of its stroke in said bore, and said plunger in a second predetermined portion of its stroke in said bore covering and closing olf said orices and the iiow of fuel through said orifices thus serving to circumferentially` lubricate said plunger during said second predetermined portion kof its stroke, whereby to divide and increase the vaporization of each charge of liquid fuel delivered to said plunger chamber only when said plunger is in said first predetermined portion of its stroke. Y

2. A fuel injector mechanism for receiving fuel under pressure from a fuel source via a supply means and for injecting the fuel into an engine combustion chamber, including in combination: f

(a) a housing having ka bore with a seat in Vits lower end and oriiice means in said seat leading into said combustion chamber,

a fuel inlet passage connecting said supply means to the lower portion of said bore above said seat by means' of a plurality of ports opening into said bore at diiferent places around said bore, and

a fuel return passage leading from an upper porl tion of said bore back to said fuel source,

(b) a fuel-injection plunger reciprocating in said bore and having a lower end adapted to engage said seat at the lower end of its fuel-injection stroke and having a side wall portion above said lower end covering and thereby closing said delivery ports at said lower` end of said stroke, said plunger when retracted from said seat uncovering said delivery ports and forming a plunger chamber between itself and said seat at the upper end of said stroke, said ports opening intosaid plunger chamber, and opposite the lower end of said plunger when said plunger is at its upward extremity, to spray fuel onto the lower end of said plunger, and a plurality of grooves successively spaced from each other and from each end of said plunger by boreengaging shoulders, the uppermost of said grooves being aligned with said fuel return passage during the full stroke of said plunger, said shoulders separating said grooves at all times from said plunger chamber times from said plunger chamber and said fuel inlet passage, (c) means engaging said fuel-injection plunger for reciprocating said fuel-injection plunger independently reservoirs to lubricate said fuel-injection plunger and said bore, and said return passage carries back to said fuel source the leakage of fuel and of gases from said combustion chamber which have passed between said shoulders and said housing bore.

4. A fuel injector for receiving fuel under pressure from a supply means and for injecting the fuel into an engine combustion chamber, including in combination:

(a) a housing having and said fuel inlet passage, 10 a bore with a seat in its lower end and orifice (c) means engaging said fuel-injection plunger for remeans in said seat leading into said combustion ciprocating said fuel-injection plunger independently chamber, and of the fuel being deposited in said plunger chamber, a fuel inlet passage connecting said supply means and to the lower portion of said bore by means of (d) check valve means in said fuel inlet passage for a plurality of delivery-ports spaced around and closing said passage during the downward fuel injecopening into said bore on a common plane, tion stroke of said plunger and keeping it closed (b) a plunger reciprocating in said bore and having a while the lower end of said plunger is seated against lower end adapted to engage said seat at the lower said seat. end of its stroke and to provide a plunger chamber 3. A fuel injector mechanism for receiving fuel under 2() between itself and said seat when said plunger is pressure from a fuel source via a supply means and for retracted from said seat, said delivery ports opening injecting the fuel into an engine combustion chamber, inirlO Said Pin-nger Chamber, cluding in combination: (c) check valve means in said fuel inlet passage for (a) a housing having closing said passage during the downward stroke of a bore with a seat in its lower end and orifice Said plunger and keeping it closed while the lower means in said seat leading into said combustion end of said plunger is seated against said seat, wherechamber, by, when said plunger is retracted and said fuel is a fuel inlet passage connecting said supply means delivered into said plunger chamber, said delivery to said bore only at the lower portion of said ports distribute the fuel charge into a plurality of bore by port means there, and a completely Sprays that all impinge onto the lower end of said separate fuel return passage leading from an plunger that has been heated by hot gases that enter upper portion of Said bore back t0 Said fuel said orifice means from said combustion chamber in Source, order to pre-heat said fuel charge before injection as (b) a fuel-injection plunger reciprocating in said bore Weil 21S t0 mX it Somewhat with hot air in said and having a lower end adapted to engage said seat Chamber, and thereby 'C0 Prepare it fOr injection at the lower end of its stroke and to provide a plunger thrOngh Seid OliCe means DtO Said Combustion chamber between itself and said seat at the upper Chamber, and end of said stroke, said port means opening into said (d) Said housing having a 10Wer end POliiOi1 bel/'0nd plunger chamber, said seat projecting into said combustion chamber a plurality of grooves successively spaced from and having a iinrled enter Surface eXPOSing a Subeach other and from each end of Said plunger stantial surface area to the hot gases in said comby bore-engaging shoulders, the uppermost of bustion chamber, so that said seat and said plunger said grooves being aligned with said fuel return Chamber are heated quickly UPOn the initial Starting passage during the full stroke of said plunger, 0f the engine, and the COOlDg effect in the plunger, said shoulders separating said grooves at all diie t0 the larger Veinlne 0f fnei Per Charge When the engine is operating under a load, is offset.

References Cited in the file of this patent UNITED STATES PATENTS of the fuel being deposited in said plunger chamber,

and gg Knudsen July 20, 1926 (d) check valve means in said fuel inlet passage for 2148182 jllV- zzzzu closing said passage during the downward fuel- 2,602,703 Camner July 8 1952 injection stroke of said plunger and keeping it closed 2,727,498 Reiners Dec. 20, 1955 while the lower end of said plunger is seated against 59 2,761,646 Noon Sept. 4, 1956 said seat, whereby said grooves act as lubrication 2,792,259 Shallenberg May 14, 1957 

1. IN A LIQUID FUEL INJECTION NOZZLE FOR THE COMBUSTION CHAMBER OF AN INTERNAL COMBUSTION ENGINE, COMPRISING A NOZZLE HOUSING HAVING A BORE THEREIN WITH A PLUNGER CHAMBER AND SEAT AT THE INNER END THEREOF AND AN ORIFICE IN SAID SEAT LEADING INTO SAID COMBUSTION CHAMBER, A FUEL INJECTION PLUNGER HAVING A CYLINDRICAL INNER END PORTION RECIPROCABLE IN SAID BORE ADJACENT SAID PLUNGER CHAMBER AND HAVING ITS LOWERMOST END PORTION ADAPTED TO MATE WITH SAID SEAT AT THE END OF THE INJECTION STROKE OF SAID PLUNGER IN SAID PLUNGER CHAMBER AND TO PROVIDE AN END WALL OF SAID PLUNGER CHAMBER WHEN SPACED THEREABOVE, A LIQUID FUEL PASSAGE IN SAID HOUSING ADJACENT SAID BORE CONNECTED TO A FUEL SUPPLY, AND A CHECK VALVE MEANS IN SAID FUEL PASSAGE; THE IMPROVEMENT COMPRISING A LIQUID FUEL CHARGE DIVIDIN AND DISTRIBUTING PASSAGE SURROUNDING SAID BORE ADJACENT THE UPPER END OF SAID PLUNGER CHAMBER, A PLURALITY OF CIRCUMFERENTIALLY SPACED SPRAY ORIFICE MEANS PROVIDING COMMUNICATION BETWEEN SAID CHARGE DIVIDING AND DISTRIBUTING PASSAGE AND SAID BORE, EACH OF SAID ORIFICES EXTENDING RADIALLY OF SAID BORE TO INJECT SAID FUEL AGAINST A DIFFERENT CIRCUMFERENTIALLY SPACED HEATER AREA OF SAID PLUNGER END PORTION WHEN SAID PLUNGER IS IN A FIRST PREDETERMINED PORTION OF ITS STROKE IN SAID BORE, AND SAID PLUNGER IN A SECOND PREDETERMINED PORTION OF ITS STROKE IN SAID BORE COVERING AND CLOSING OFF SAID ORIFICES AND THE FLOW OF FUEL THROUGH SAID ORIFICES THUS SERVING TO CIRCUMFERENTIALLY LUBRICATE SAID PLUNGER DURING SAID SECOND PREDETERMINED PORTION OF ITS STROKE, WHEREBY TO DIVIDE AND INCREASE THE VAPORIZATION OF EACH CHARGE OF LIQUID FUEL DELIVERED TO SAID PLUNGER CHAMBER ONLY WHEN SAID PLUNGER IS IN SAID FIRST PREDETERMINED PORTION OF ITS STROKE. 